Polarisation insensitive 1300 nm laser amplifiers employing both compressively and tensile strained quantum wells in a single active layer

Polarization insensitive operation was obtained fro 1300 nm multiple quantum well (MQW) semiconductor amplifiers by incorporating three tensile strained and four compressively strained wells in a single active layer. By the introduction of window regions at the facets, the performance could be improved even further leading to 22 dB fiber to fiber gain for both the transverse electric (TE) and transverse magnetic (TM) polarization directions. The window regions lead to a reduction of the facet reflectivity down to a value of 3 × 10^-5, while at least maintaining the high chip to fiber coupling efficiency. In addition, a record low fiber coupled noise figure of 6 dB and a fiber coupled saturation output power of 13 dBm were obtained